1. Field of the Invention
The invention relates to a communication system which performs a communication by using a plurality of frequencies.
2. Related Background Art
In recent years, a cordless telephone system has widely been spread and a cordless telephone system of a large scale in which a slaves are dynamically area controlled is being spread.
In such a system, in the case where the slave is moved to another area during the communication and the master connected is switched, a carrier sensing operation or the like is executed and a new communication channel is used.
Since the communication channel is switching as mentioned above, however, a hardware-like instantaneous shut-off time which is required to switch the communication channel (frequency) exists. To reduce such an instantaneous shut-off time, a radio hardware having a high speed synthesizer is used or a plurality of radio units are installed. Such a method results in an increase in costs.